Siemens SIRIUS 3RW30 Manual page 46

Functions
5.3 Motor protection / intrinsic device protection (3RW40 only)
Recovery time (intrinsic device protection)
If the intrinsic device protection is tripped, the soft starter cannot be restarted until a recovery
time of at least 30 seconds has elapsed upon overload of the thyristors and at least
60 seconds upon overload of the bypasses.
Thyristor protection (short-circuit)
SITOR semiconductor fuses must be connected upstream to protect the thyristors against
short-circuits (e.g. in case of cable damage or an interturn fault in the motor; refer to chapter
Soft starter assembly with type of coordination 2 (Page 74)). For the fuse selection tables,
refer to chapter Technical data (Page 127).
Protection against voltage failure (in the event of a fault)
If the control supply voltage fails during a trip, the current tripping state of the thermal
intrinsic device protection model and the current recovery time are stored in the soft starter.
When the control supply voltage is restored, the current tripping state of the thermal intrinsic
device protection prior to the power failure are likewise automatically restored.
Note
If the control voltage is disconnected during operation (e.g. in "automatic mode"), the starter
is not protected against voltage failure. You must wait five minutes between two starts to
ensure that the motor protection and the intrinsic device protection are working correctly.
46
SIRIUS 3RW30 / 3RW40
Manual, 10/2018, NEB535199502000/RS-AB/005